1. Field of the Invention
The present invention relates to a lead frame having an LED (Light Emitting Diode) carried and mounted thereon, its manufacturing method, and a semiconductor light emitting device using the same.
2. Description of the Related Art
Generally, a lead frame having an electronic device such as a semiconductor integrated circuit or an LED device carried and mounted thereon is manufactured of a lead frame metal thin plate made of copper thin plate, iron/nickel alloy thin plate, copper/nickel/tin alloy thin plate or the like. Specifically, the lead frame is manufactured by using an etchant such as ferric chloride from either side or both sides of a metal material for photoetching. Alternatively, the lead frame is manufactured by punching using a press mold. The lead frame comprises a pad (island part) configured to mount a semiconductor integrated circuit or LED device thereon, an inner lead and an outer lead which are insulated and separated from the pad. The inner lead is electrically connected to an electronic device. The outer lead is electrically connected to the outside and extends from the inner lead.
The lead frame includes a mounting part (mounting surface) configured to mount an electronic device on the upper surface of the pad. Further, there has been known a lead frame including a radiator (heat radiating plate) configured to radiate drive heat generated from a body of an electronic device such as LED device on the lower surface of the pad or heat due to environmental conditions around the electronic device. In other words, the lead frame is configured such that the heat is radiated from the radiator on the lower surface of the pad or the outer lead to the outside so as to prevent the heat from being accumulated in the electronic device.
A substrate configured to mount electronic devices such as a semiconductor integrated circuit or an LED device employs a ceramic substrate, a printed circuit board or the like in addition to the lead frame substrate using a lead frame made of metal thin plate. However, the radiator formed on the pad on which the electronic device is mounted is desired to be as wide as possible in its radiating area in terms of heat radiating efficiency. Patent Literatures 1 to 5 describe therein techniques for mounting an electronic light emitting device such as LED on a carrier and heat radiating techniques for preventing heat from being accumulated in a light emitting device.